Noboru Furuya

Ferroelectric Random Access Memory Using Pb(Zr,Ti,Nb)O 3 Films

We have succeeded in fabricating Pb(Zr,Ti,Nb)O3 (PZTN) thin films with 20-atomic% Nb at B site in ABO3 structure, which was suitable for high density and reliable ferroelectric random access memory (FeRAM). A sol-gel spin-coating method was used to prepare the PZTN thin films. 1 mol% Si co-doping was applied to promote the solid-solution of Nb atom into the original Pb(Zr,Ti)O3 films. We suggested that in our PZTN the oxygen vacancies were well suppressed due to Nb substitution comparing with conventional Pb(Zr,Ti)O3 (PZT). We also succeeded in obtaining excellent electric properties in 1times1 mum2 capacitors with PZTN. In addition, we confirmed the no data degradation and the high reliability of our PZTN material has been demonstrated by 64 k-bits FeRAM chip operation.